Temperature compensating device



y 3 v. E. CARBONARA 1,966,753

TEMPERATURE COMPENSATING DEVICE l8 J9 IO N 27 26 INVENTOR ViCTQR CARBONARA Patented July 17, 1934 UNITED STATES I I 1,966,758. TEMPERATURE COMPENSATING DEVICE- Victor E. Carbonara, Brooklyn, N. Y., assignor to Pioneer Instrument Company, Incorporated, Brooklyn, N. Y., a corporation of New York Application June 13, 1929, Serial No. 370,517 Renewed December 12, 1933 9 Claims.

device may be varied at will so as to enable an accurate setting to be made which will suffice for temperature compensating needs of a particular instrument.

Another object of the invention is to provide a temperature compensating device which is so designed as to enable easy adjustment thereof for use with diiferent instruments requiring special adjustment in the matter of caring for correctivemeasures required because of changes in temperature.

Other objects and advantages will be pointed out hereinafter in the description of the invention and in the claims.

In the drawing:

Fig. 1 is a side elevation of a temperature compensating device utilizing the principle of my invention.

Fig. 2 is a side elevation of the temperature compensating device illustrated in Fig. 1, but arranged for a different compensating value.

Fig. 3 is a perspective view of a temperature compensating device mounted as a unit ready for installation in an instrument.

Fig. 4 illustrates the manner in which the compensating unit is used in an altimeter.

The form of the invention which I have illustrated is my preferred form because it is of a simple construction and readily lends itself to practical requirements. A bar has secured to a flat side a bi-metallic member 11 which may be made of two strips of different materials, such as invar and brass, which are commonly used for such members. As is well understood changes in temperature cause a bi-metallic member formed in the manner related to hex. As used by me, one end of the invar strip extends beyond the other strip and is firmly secured to bar 10 whereby the entire bi-metallic member 11 is supported 45 by the bar with one end permanently anchored thereto. The other end is free to assume whatever shape its character imposes upon it at an existing temperature except to the extent hereinafter to be disclosed.

The temperature compensating devicemade up of the bar 10 and the bi-metallic member 11 has associated therewith adjustable means adapted to maintain the bi-metallic member and the bar in spaced relation so that when the device is assembled in an instrument, adjustment may be made between the bar 10 (and its associated element in the instrument) and the free end of the bi-metallic member 11 (and its associated element in the instrument). The adjustable means provided for this purpose may conveniently take the form of a screw 12 engaging one of a series of tapped holes 13, 14, 15 and 16, Fig. 3.

The end 17 of the screw is preferably pointed as a matter of refinement and to establish a deli nite point of contact with the bi-metallic memher. As indicated by ghost lines in Fig. 1 as compared with the full line position of the bi-metallic member, the end 17 of screw 12 restricts the movement of the bi-metallic member 11 during changes in temperature.

The adjustment permitted by possible changes in the engaged relation of the screws 12 within a single hole is very useful when a particular instrument with which the device is to be used, is tested and calibrated. However, in order to render the degree of adjustment as fine as is possible to suit the exacting requirements of recision measuring instruments and also to enable standard temperature compensating devices to be fabricated for application to any one of numbers of instruments manufactured according to a set of specifications, it is desirable that several tapped holes such as 13, 14, 15 and 16 be provided along the length of the bar 10. These holes enable the point of contact between screw 12 and the bi-metallic member to be shifted so as to make available many more differences in relation of the free end of the bi-metallic member 11 to the bar 10. As may be seen in Fig. 2, with screw 12 engaging hole 16, the bi-metallic member 11 will assume diiferent forms for changes in temperature from the forms which are assumed for corresponding differences in temperature when the screw 12 is in hole 13, as in Fig. 1.

By way of illustrating an application of the invention I have shown the temperature compensating device as used in connection with an altimeter. The altimeter has an expansible box '18, Fig. 4, formed byelastic diaphragm and from which air is partly removed. The bottom\side of the box is anchored-as at 19 and the top side is free to rise and fall under the action of changes in atmospheric pressure. A steel spring 20 holds the top of the box in position against external pressure by means of a short pillar 21 secured to the center of the top of the box, but at the same time the spring is sufficiently flexible to yield to any variations in pressure. The free end of spring 20 carries a collar 22 from which extends a hollow element 23. The rod 10 is secured to the member 11 has a pin connection 24 with an element 25.

As the expansible box expands and contracts rod 10 rises and falls and in turn controls element 25 whose lower end is pivoted to an arm 26. Arm 26 is fixed to a. pivot rod 27 to which is also fixed an arm 28. A flexible element 29 is connected to arm 28 by means of a link 30 and it is also connected toa drum 31 mounted upon hand-staff 32. As atmospheric pressure decreases, rod 10 rises and arm 28 moves to the left. Concomitant with this action hair spring 33 causes the rotation of the hand staff 32 an amount corresponding to the amount of movement of arm 28 and associated elements. The flexible member 29 is maintained taut and lost motion between the controlled and the controlling parts is prevented by the hair-spring 33.

Thedetails of construction of the altimeter apart from the temperature compensating device form no part of the present invention, but are illustrated herein in order to exemplify a practical embodiment of my invention in a precision measuring instrument. Temperature compensating devices are useful with many types of instruments and it is contemplated that variation may be made in the present invention to accommodate it for use with different kinds of instruments without departure from the nature and principle thereof. Its use for maintaining a constant relation between associated elements in a chain of linkage over a range of temperature changes is apparent and I therefore do not restrictmyself unessentially in the foregoing or other particulars, but contemplate such alterations and modifications within the scope of the appended claims as may be found advisable.

l. The combination in a precision measuring instrument having elements and connections to transfer motion from one element to another,-of

a bi-metallic member supported at one of its ends by oneof said elements, means at the other end of said member connecting the same with another of said elements, and means variably adjustable along the length of said member whereby'different temperature compensating values may be had for different positions of said means.

2. The combination in a precision measuring instrument having a controlling unit, a bar operated thereby and linkage movable by said bar, of

a bi-metallic member having one end secured to said bar and a portion thereof spaced from said banfmeans connecting the linkage to said biperature compensating effects because of said bimetallic member may be had.

4. In combination, a temperature'compensating device comprising a bar, a bi-metallic mem ber carried by said bar, said bi-metallic member being spaced along a portion of its length from said bar, means engaging said bar and member and holding the spaced length of said member in separated relation with said bar, said means being adapted to cooperate with said bar and member in different positions along their spaced lengths by engagement in different holes along the length of said bar and in contact with the bi-metallic member.

5. In combination, a temperature compensating device comprising a bar, a bi-metallic member comprising two strips one of which has one end extending beyond the adjacent end of'the other strip and attached to said bar, and means engaging said bar and member for holding the unattached end of said member in spaced relation with said bar, said means being adjustable to enable variable setting of the angular relation of said member and bar.

6. In combination, a temperature compensating device comprising a bar, a bi-metallic membercomprising two strips of metal fastened to-' gether, one of said strips having one end extending beyond the adjacent end of the other strip and attached to said bar, and means comprising an element adapted to engage said bar and member by contact therewith in any one of a series of holes provided along said bar, said element being adjustable to flex the bi-met'allic member for altering the angular relation of the bar and member.

'I. The combination in a precision measuring instrument having a system of links and levers pensating member included in said system and forming a functional part thereof in transmitting said motion whereby the eifect of thermal expansion of said elements may be nullified by a counter-effect produced in said member, said member including a bar and a thermal unit secured to said bar at one end and spaced therefrom adjacent said end,'and adjustable means adapted to engage said bar and unit at any one of a plurality of points therealongfor varying the spaced relation of said bar and unit for any one temperature without shifting the longitudinal position of the unit relative to the bar, whereby the measuring instrument may be compensated for thermal expansion at various temperatures.

8. In a precision instrument of the class described, the combination of pressure sensitive means, indicating means, and mechanism for transmitting motion from the first named means to said second named means, said mechanism including -a supporting member having a plurality-of openings therein, a temperature sensitive member carried by said supporting member to compensate temperature errors of said pressure sensitive means, and means adapted to extend through any one of said openings into engagement with said. temperature sensitive member whereby the temperature compensating effect of the latter is varied.

9. In an altimeter including an aneroid and a member connected to said aneroid at the operating axis thereof and actuated therewith upon expansion and contraction of said aneroid, said member having a portion'adjacent said aneroid.

fldevicehaving one end connected to said member at said adjacent portion, said thermostatic device being movable with said member and extending transversely of said aneroid axis perpendicularly to a plane containing said axis, and having its effective length adjustable toward and away from said plane containing .said aneroid axis, and indicating mechanism pivot'ally conn'ected-to the free end of said thermostatic de-,

vice,

VICTOR E. CARBOHARA. 

